Eliminating tooth decay: Breakthrough in dental plaque research

Dec 07, 2010

Dutch professors Bauke Dijkstra and Lubbert Dijkhuizen have deciphered the structure and functional mechanism of the glucansucrase enzyme that is responsible for dental plaque sticking to teeth. This knowledge will stimulate the identification of substances that inhibit the enzyme. Just add that substance to toothpaste, or even sweets, and caries will be a thing of the past. The results of the research have been published this week in the journal Proceedings of the National Academy of Sciences (PNAS).

The University of Groningen researchers analysed glucansucrase from the lactic acid bacterium Lactobacillus reuteri, which is present in the human mouth and digestive tract. The bacteria use the glucansucrase enzyme to convert sugar from food into long, sticky sugar chains. They use this glue to attach themselves to tooth enamel. The main cause of tooth decay, the bacterium Streptococcus mutans, also uses this enzyme. Once attached to tooth enamel, these bacteria ferment sugars releasing acids that dissolve the calcium in teeth. This is how caries develops.

Using protein crystallography, the researchers were able to elucidate the three dimensional (3D) structure of the enzyme. The Groningen researchers are the first to succeed in crystallizing glucansucrase. The crystal structure has revealed that the folding mechanism of the protein is unique. The various domains of the enzyme are not formed from a single, linear amino acid chain but from two parts that assemble via a U-shaped structure of the chain; this is the first report on such a folding mechanism in the literature.

The unravelling of the 3D structure provided the researchers with detailed insight into the functional mechanism of the enzyme. The enzyme splits sucrose into fructose and glucose and then adds the glucose molecule to a growing sugar chain. Thus far the scientific community assumed that both processes were performed by different parts of the enzyme. However, the model created by the Groningen researchers has revealed that both activities occur in the same active site of the enzyme.

Dijkhuizen expects that specific inhibitors for the glucansucrase enzyme may help to prevent attachment of the bacteria to the tooth enamel. Information about the structure and functional mechanism of the enzyme is crucial for developing such inhibitors. Thus far, such research has not been successful, states Dijkhuizen: The various inhibitors studied not only blocked the glucansucrase, but also the digestive enzyme amylase in our saliva, which is needed to degrade starch.

The crystal structure also provides an explanation for this double inhibition. The data published by the Groningen scientists shows that glucansucrase proteins most likely evolved from amylase enzymes that degrade starch. We already knew that the two enzymes were similar, says Dijkhuizen, but the crystal structure revealed that the active sites are virtually identical. Future inhibitors thus need to be directed towards very specific targets because both enzymes are evolutionary closely related.

Dijkhuizen points out that in future glucansucrase inhibitors may be added to toothpaste and mouthwash. But it may even be possible to add them to sweets, he suggests. An inhibitor might prevent that sugars released in the mouth cause damage. However, Dijkhuizen doesnt expect that toothbrushes have had their day: it will always be necessary to clean your teeth.

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User comments : 33

Good, maybe we can sneak this by the dental industry. And maybe then we can put a stop to the government sanctioned mass- drugging thats coming out of our tap in the form of fluorides. Think about it. How is it ok to cause millions of people to ingest a drug for the rest of their lives that only (topically) benefits the enamel of children under 12?

Dear Mercury, flouride is extremely effective for both adults and children. 1)the flouride ion is taken up even by adult enamel to make that enamel more resistant to decay2) flouride has also been shown to have bacteriostatic effects, which can benefit both adults and childrenWater flouridation has been shown to be one of the greatest public health benefits of the 20th century. In some communities, the public has been exposed to disinformation and public health officials are having to re-educate the public to the need for flouride. Since I extract decayed teeth for living, I would benefit incredibly by removing flouride from the public water supply. But flouridation works, has been shown to be safe, and saves the US probably billions in dental care and time away from work each year.

I can no longer sit back and allow communist infiltration, communist indoctrination, communist subversion, and the international communist conspiracy to sap and impurify all of our precious bodily fluids.

"Water flouridation has been shown to be one of the greatest public health benefits of the 20th century."

that's why most european countries have stopped fluoridation of their water. And of course we all know that science in the US is better than in Europe so maybe those old countries don't know what they are doing.

If you're worried about fluoride, just install a reverse osmosis system. They've become remarkably cheap ($150 at Costco last I saw), last a long time with little maintenance, and remove a lot of nasties from the water.

Bottled water certainly isn't a solution. Plenty of studies have shown that bottled water tends to be worse than tap water.

That substance that you need to add to the toothpaste, the sweets and everything else containing ordinary sugar is called Xylitol! It is as sweet as sugar, is natural, prevents caries, is readily available and has a very low glycemic index of about 8 and has an activly inhibiting profile on strep. mutans. I wonder what they teach the dentists at the dental schools and universities? Are they worried that they run out of work?

Fluoride was discovered, in an African tribe. They had so much fluoride in the water their teeth were brown but cavity free. I never heard of them having any problems from ingesting their whole lives many times what we do.

That substance that you need to add to the toothpaste, the sweets and everything else containing ordinary sugar is called Xylitol! It is as sweet as sugar, is natural, prevents caries, is readily available and has a very low glycemic index of about 8 and has an activly inhibiting profile on strep. mutans. I wonder what they teach the dentists at the dental schools and universities? Are they worried that they run out of work?

This is not the solution for all of the tooth problems, I know people not eating sweets and still have problems, the real problem here is that all our food is greatly processed, all the carbs (bread and stuf) are easily taken by microbs and then the decay starts, brush your teeth after every meal and you wont have eny problems(there is great difference and it involves to brush them 3 times not 2 every day not so hard to do), i cant remember how my dentist looks like(havent seen him for 6 years), and I eat sweet things after every meal.

And even if it does help build enamel in adults, why ingest it? How is it ok to add a drug to the public water supply? Do your research and find out whos idea this was, and who got paid to publish the only "studies" showing the benefits of fluoridation.

I should clarify my previous comment. I believe the benefits of fluoridation far outweigh the [perceived] risks, I'm only trying to show that it's silly to complain about fluoridation because it is so easy and inexpensive to remove fluoride from your drinking water.

That said, congratulations to the authors. I hope this leads to some practical applications in the near future.

Yes, Bog Mire, I recommend flouridation, even though I know that it hurts my business. I have no vested interest in recommending flouride. I recommend flouride because it is unethical not to. There is no "money trail". When I prescribe flouride for people with rampant decay, I see reversal of small cavities and hardening of all enamel within months. It is possible to overflouridate. Too high a level of flouride in the water creates mineralization defects and brown discoloration. And yes, dental students are taught that sugar free gum is extremely beneficial for teeth. Dhinjs, I recommend you add flossing to your regimen. There are plenty of people out there who wear dentures because they "brushed three times a day" but never flossed.

In regards to fluoride. People that have a problem with it (think it is a unnatural additive to water) tend not to know that it IS completely a natural additive to water (as in it exists extensively naturally in "clean" water). And so much so that many of the "fluoridation plants" includes actually reducing fluoride in quite a few locations (as will as adding it in others) it is much much more a regulation of a useful and save level then any crazy conspiracy to ADD it to all water for some nefarious plan.

Actually i didnt mentioned it but i use flossing(again after every meal-maybe here I go too far), and something else actually I dont drink and eat too cold or hot stuff and I avoid sour apples and lemons(the orange has more vit C, it is not a great loss), this is not like the sweet, it acts directly on your enamel, with sweets you have some time before they turn to acids, lots of people dont get that and torture themselves greatly with not eating anything with sugar in it.

@Eroq: Nobody ever said it was a conspiracy or some nefarious plan. (straw man logic). and youre wrong anyway. average trace amount of fluorides in ground water are around .4ppm. The added fluorides in the water where I live are at 4ppm. At this level, 8oz of water is about the same as in a pea sized dab of toothpaste, which we all know we arent supposed to swallow. Just read the "drug facts" on the back of the tube. And to the dentist: If fluoride treatment does work for adults, then I wouldnt mind having it done myself. Im sure it has its benefits, and i use it in my toothpaste and rinse to kill bacteria. Im glad it also builds enamel, but Im not going to ingest it every day for the rest of my life. It builds up in our bones. It also bonds to aluminum in the body and then builds up in our endocrine system. The biggest reason we put this stuff in our water is that fertilizer and chemical industries needed some way to dispose of their toxic waste. Its simple economics, not a plot.

It's nice to live in a location where the municipal water isn't fluoridated. I still filter out the chlorine though. Worrying about fluoride when there's chlorine in your water seems misguided.

For those avoiding fluoride ingestion, watch out for tea. Fluoride bioaccumulates in tea leaves to a very strong extent, and has increased over the last few decades due to pollution. I suppose that "white" tea, made from young leaves, would be safer.

I suspect that using green tea as a mouthwash that is not swallowed would be beneficial to one's dental health.

I can no longer sit back and allow communist infiltration, communist indoctrination, communist subversion, and the international communist conspiracy to sap and impurify all of our precious bodily fluids.

Good, maybe we can sneak this by the dental industry. And maybe then we can put a stop to the government sanctioned mass- drugging thats coming out of our tap in the form of fluorides. Think about it. How is it ok to cause millions of people to ingest a drug for the rest of their lives that only (topically) benefits the enamel of children under 12?

I agree with you on facts but would it not be a lot simpler to substitute sugar in food, drinks and toothpaste with the healthy alternative Xylitol? After all how many people clean their teeth 3 times a day, eat a low refined carbohydrate diet and don't drink soft drinks? By the way I have no shares in Danisco but know how effectiv Xylitol is. To verify you may read all the studies done in Finland in the 30 years or so after WW2 concerning the benefits of Xylitol!

Dentists have been rendered obselete decades ago already by discoveries similar to this -- these discoveries suppressed by big business in order to continue raping us for money. Business as usual, this one will never happen either.

I can no longer sit back and allow communist infiltration, communist indoctrination, communist subversion, and the international communist conspiracy to sap and impurify all of our precious bodily fluids.

You forgot to mention that Communism is evil and also a generally bad idea.

Actually i didnt mentioned it but i use flossing(again after every meal-maybe here I go too far), and something else actually I dont drink and eat too cold or hot stuff and I avoid sour apples and lemons(the orange has more vit C, it is not a great loss), this is not like the sweet, it acts directly on your enamel, with sweets you have some time before they turn to acids, lots of people dont get that and torture themselves greatly with not eating anything with sugar in it.

I can no longer sit back and allow communist infiltration, communist indoctrination, communist subversion, and the international communist conspiracy to sap and impurify all of our precious bodily fluids.

You forgot to mention that Communism is evil and also a generally bad idea.

I purposely didn't put quotes around that movie line to see if anyone is as big a fan of Dr. Strangelove as I am. I guess I'm alone here.

HEY FOLKS, STOP EATING ALL THE CRAP and maybe you're teeth won't be as rotten. Is anyone aware of how much sugar (in all its processed and unprocessed forms) we eat? Then we won't have to worry about needing extra chemicals just to stay healthy with healthy teeth.

For my part, most non-sugar sweeteners either give me a headache or diarrhea. I have friends who have a similar problem with sweeteners (and two who can't stomach HFCS), so you can't tell me it is a healthy alternative.

If you are stressed about flouride, there are some pretty cheap filters that take it out along with the chlorine. Very simple problem to solve.

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